We then examined which particular DMN subregions show strongest predictive associations with fornix microstructure differences (Fig. 2C). Robust contributions to this predictive relationship (bagging) were apparent in the right and left temporoparietal junctions (TPJs) [weightR_TPJ-1 = −0.61 ± 0.04 (SD of bootstrap distributions), weightR_TPJ-2 = 0.75 ± 0.07, weightL_TPJ-1 = −0.25 ± 0.06, and weightL_TPJ-2 = −0.18 ± 0.07], medial portions of left ventromedial prefrontal cortex (vmPFC; weightL_vmPFC-1 = 0.17 ± 0.03, weightL_vmPFC-3 = −0.64 ± 0.07), left middle temporal gyrus (MTG) (weightL_MTG-2 = −0.32 ± 0.05, weightL_MTG-3 = 0.31 ± 0.04), and in the dorsal posterior cingulate and retrosplenial cortex (weightPMC-3 = −0.13 ± 0.09, weightPMC-4 = 0.18 ± 0.03). We conclude that especially the right TPJ, its left counterpart, the left vmPFC, and posterior parts of the left MTG, as well as the posterior cingulate and retrosplenial midline were found most relevant among DMN gray matter patterns that predict fornix microstructure.
